Aargh
The “gh” is silent 
Yeah, I think the deal with “argh” is that it is just someone’s spelling. I would spell it “aww”, but somebody might pronounce that with an overemphasized w, as in “awwwwwwh!”. Plus, “argh” means, “I am experiencing unpleasant physical sensations, or emotions so potent they resemble physical sensations”, while “aww” means “Hey, now, let’s be reasonable”.
People’s pronunciation of these mumble sounds enters the language, and creates new words. I actually have heard people say “arg!”, probably in imitation of what they’ve read. Another one I’ve heard is “faw”, which is probably derived from the written “faugh”, which should really be pronounced “pfff”.
And then there’s Homer Simpson’s “doh!” which is pronounced very staccato, with only a short d-sound … it is becoming accepted as a much more legato sound “doe”, like someone say “no” while holding their nose.
Another one: the recent A Christmas Carol features a much lower “Bah! Humbug!” factor than most other productions. Jean-Luc Picard plays Scrooge (poor fella, can’t remember his real name, just the names of his characters). He heavily de-emphasizes the “bah”, since again, it’s just a mumble that the written medium forced Dickens to spell. Written today, Picard’s pronunciation would be spelled more like “awww, hum bug!” But literal readings of Dickens are rarely like this.
I dunno, I say “Argh!” all the time, just the way it’s spelled. And it usually has nothing to do with ARG220 (although sometimes it did in the past!)
Soup - the exhalation explaination makes sense.
Boris - Picard/Scrooge’s real name is Patrick (why doesn’t that spelling look right?) Stewart.
Eschew Obfuscation
Y’know Tengu, I must have first read that comic book 25 years ago, and that exhalation explaination never occured to me until now. I love this message board! It really wakes the old brain cells up!
Don’t it, though, soup?
Not sure where the ‘g’ came from in ‘paag’, but, sound effects are full of extrainious letters.
Eschew Obfuscation
I suspect that the reason that the spelling “argh” is used for an exclamation is that gh is used to stand for a back of the throat k or h sound. Such a sound used to exist in English, and it exists in many other languages. The reason for the gh in words like “night” or “through” is that at one point, hundreds of years ago, those words were pronounced with a back of the throat k or h sound, but a sound change caused it to disappear from English.
Also, the reason that the r is in the spelling is that it’s being written for someone speaking an r-less dialect. You can’t actually hear what those of us who speak an r-ful dialect think of as an r sound. The closest spelling that I can think of to what “argh” is supposed to sound like is “aw” or “ah”, but that’s not very close.